Sole for footwear for unstable surfaces

ABSTRACT

A sole for footwear that is suited for sandy or non-rigid environments, as well as various footwear that includes the sole, are disclosed. The sole includes a first arc structure extending along a forefoot portion of the sole, and a second arc structure extending along a rear foot portion of the sole. The second arc structure has an open end that faces an open end of the first arc structure, and the second arc structure is separated from the first arc structure by a gap. The stability and traction structure further includes a linear structure extending from within the first arc structure to within the second arc structure.

BACKGROUND

This present invention is related to footwear, and more particularly to a sole for footwear that is adapted for unstable surfaces.

Walking, jogging, and running are forms of human activity that are thought to be natural and beneficial to health and well-being. These activities are often performed on stable, supportive surfaces. However, there are a lot of areas where walking, jogging and running are difficult due to unstable terrain. These areas include sandy or gravel-filled beaches of oceans, lakes or rivers, muddy or wet areas, desert terrain, and other areas with unstable pedestrian surfaces. What is needed is footwear that can adapt to, and overcome, the instability and inefficiency of unstable terrain to enable a wearer to better walk, jog and run on such terrain.

SUMMARY

This document describes a sole for footwear that is suited for sandy or non-rigid environments, as well as various footwear that includes the sole.

In one aspect, a stability and traction structure for a footwear sole is disclosed. The stability and traction structure includes a first arc structure extending along a forefoot portion of the sole, and a second arc structure extending along a rear foot portion of the sole. The second arc structure has an open end that faces an open end of the first arc structure, and the second arc structure is separated from the first arc structure by a gap. The stability and traction structure further includes a linear structure extending from within the first arc structure to within the second arc structure.

In another aspect, a sole for footwear for unstable environments is presented. The sole includes a planar bottom side, and a peripheral elongated protrusion extending down from the planar bottom side along a periphery of the sole and having a gap between a forefoot portion and a rear foot portion of the sole. The sole further includes a linear elongated protrusion extending down from the planar bottom side substantially in the middle of the peripheral elongated protrusion.

In yet another aspect, a sandal is described. The sandal includes a sole having a top side and bottom side, and a strap connected to the top side of the sole for fastening to a foot of a wearer of the sandal. The sandal further includes a first elongated protrusion extending down from the bottom side along a periphery of a forefoot portion of the sole and a second protrusion extending down from the bottom side along a periphery of a rear foot portion of the sole. The sandal further includes a third elongated protrusion extending down from a medial portion of the bottom side and bridging the forefoot and the rear foot of the sole.

The sole and the stability and traction members that it provides can be implemented with other types of footwear, including but not limited to, boots, shoes and sand shoes. The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with reference to the following drawings.

FIG. 1 illustrates a stability and traction arrangement for a sole for footwear.

FIG. 2A is a top perspective view and FIG. 2B is a bottom perspective view of a sandal that incorporates a sole in accordance with implementations described herein.

FIG. 3A is a side view and FIG. 3B is a bottom view of a boot that incorporates a sole in accordance with implementations described herein.

FIG. 4A is a top perspective view and FIG. 4B is a bottom view of a sand show that incorporates a sole in accordance with implementations described herein.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This document describes a sole for footwear that is suited for sandy or non-rigid environments, as well as various footwear that includes the sole. The sole combines equine biomechanics and horseshoe technology with human biomechanics and gait to produce a structure that provides stability for a human walker, jogger or runner on unstable surfaces.

A sole in preferred implementations utilizes a stability and traction mechanism that incorporates a “double horseshoe” arrangement, i.e. two U-shaped structures with open ends facing toward each other, implemented by first and second arc structures facing each other by their open ends and separated by a gap. The sole further includes a linear structure extending from within the first arc structure to within the second arc structure, to provide, in addition to added stability, balance and control like a frog of a horse's hoof. The first arc extends along a periphery of a forefoot portion of the sole, and the second arc extends along a periphery of a rear foot portion of the sole. In addition, the sole is formed and made of a resilient material for attenuating shock and vibration associated with use and to provide maximum traction to a wearer on unstable surfaces or non-rigid environments.

The preferred, exemplary implementations are illustrated in FIG. 1, showing left and right soles 101 and 102, respectively. Each sole 101, 102 includes a first arc structure 104 extending along a periphery of a forefoot portion 106 of the soles 101, 102, and a second arc structure 108 extending along a periphery of a rear foot portion 110 of the soles 101, 102. Each sole 101, 102 further includes a linear structure 114 that extends from within the first arc structure 104 to within the second arc structure 108.

Each of the first and second arc structures 104, 108 are preferably “horseshoe” shaped, arranged with open ends facing each other, and separated by a gap 112. The gap 112 enables the first and second arc structures 104, 108 to operate independently. In preferred implementations, the gap 112 is aligned and coextensive with a line of flexion of a foot of the wearer, such as a medial metatarsal-phalanges joint line, for instance.

The first and second arc structures 104 and 108 and linear structure 114 can be formed of a protrusion, such as approximately half of a cylindrical tube, for example. The first and second arc structures 104 and 108 and linear structure 114 can be solid or hollow, but are at least slightly compressible and flexible. Suitable materials for the first and second arc structures 104 and 108 and linear structure 114 of the soles 101, 102 include rubber, polyvinyl carbonate (PVC), nylon, other plastics, metal, or other materials. The soles 101, 102 provide a larger surface area than typical soles, and provide a wider and more even surface area to an unstable surface than the foot, to disperse the weight and force of impact on the unstable surface.

In operation, the foot of a wearer of the soles 101, 102 comes down onto an unstable surface in two parts: the back of the foot comes down, plants and is stabilized by the second arc structure 108. The forward-facing U-shape of the second arc structure 108 further attenuates shock and vibration, while inhibiting too much sliding forward of the sole (or footwear to which it is attached) as the back of the foot comes down. The linear structure 114 then provides more surface area connection with the unstable surface, keeps the foot level, and inhibits or counteracts over arching of the foot. Finally, the front of the foot comes down, where the first arc structure 104 adds further stability, grabs or scoops the unstable surface, and provides leverage against it. Accordingly, the use of the presently described soles 101, 102 and the traction structure provided thereby for various types of footwear, can significantly decrease instances of ankle injury due to surface instability, and unstable surfaces can now be available as a suitable or even desired place for walking, jogging or running.

FIGS. 2A and 2B show a sandal 200 using a sole and traction structure as described above. The sandal 200 includes a sole 202 having a top side 204 and a bottom side 206. The top side 204 can be substantially planar, or may be contoured to accommodate a foot of a wearer of the sandal 200. For example, the top side 204 can include indentations for receiving a heal, forefoot, and/or toes of a foot. The top side 204 may also include a ridge or arch support structure. The sandal 200 also includes a strap 208 connected to the top side 204 of the sole 202 for fastening to the foot of the wearer of the sandal 200.

The bottom side 206 is preferably planar or substantially planar, at least in part. In some implementations, the bottom side 206 is smooth and water-impermeable, to inhibit collection of sand, dirt or other particulate, or inhibit absorption of water or other fluids. In other implementations, the bottom side 206 may include small ridges or a pattern for providing traction or grip to a surface or environment, such as a sandy beach, on which the wearer walks.

The sandal 200 further includes traction members 210 extending down from the bottom side 206. In some implementations, the traction members 210 include a peripheral elongated protrusion 212, 214, similar to the first and second arc structures 104, 108 of FIG. 1, extending down from the bottom side along a periphery of the sole 202 and having a gap 218 between a forefoot portion and a rear foot portion of the sole. In exemplary implementations, the gap 218 is aligned and coextensive with a line of flexion, such as a medial metatarsal-phalanges joint line of a foot of the wearer. The gap 218 can be formed as a cut-out or tapering of the peripheral elongated protrusions.

The traction members 210 may also be formed of a first elongated protrusion 212 extending down from the bottom side 206 of the sole 202 along a periphery of a forefoot portion of the sole 202, and a second protrusion 214 extending down from the bottom side 206 of the sole 202 along a periphery of a rear foot portion of the sole 202. The sandal 200 may include a third, or medial, elongated protrusion 216 extending down from a medial portion of the bottom side 206 and bridging the forefoot and the rear foot of the sole 202, for extra support and resistance against too much bending of the sole 202 at the gap 218.

In preferred implementations, the traction members 210 of the first, second and third elongated protrusions 212, 214, and 216, respectively, are formed as curved (peripheral) or straight (medial) in the shape of a half-cylinder or part-cylinder. In other implementations, the traction members 210 are squared or angular. The traction members 210 can be solid, cellular, or may include one or more larger air pockets or channels, or may be formed of a number of small, serial protrusions. The traction members 210 may also be formed with an inner material that is denser or lighter than an outer material. More than two layers are possible.

The sandal 200 can be made of rubber, foam, polyurethane, leather, plastic, or any other rigid or flexible material, such as alloys or composite materials. Alternatively, the materials used for the sandals 202 can be soft and compressible, or a combination of hard, resilient materials with soft, compressible materials. In some implementations, the sole 202 can be formed of layers of different materials, and in still other implementations, the traction members and/or bottom side 206 of the sole 202 can be formed of a softer material than the top side 204 of the sole 202. Sandals 200 can be injection molded, thermally bonded, etc, in a manufacturing process. The protrusion may have an interior cavity made using a blow molding process.

FIG. 3A is a side view and FIG. 3B is a bottom view of a boot 300 that incorporates a sole 302 in accordance with implementations described herein. FIG. 4A is a top perspective view and FIG. 4B is a bottom view of a sand shoe 400 that incorporates a sole 402 in accordance with implementations described herein.

Although a few embodiments have been described in detail above, other modifications are possible. For example, the stability and traction mechanism and sole can be applied to other types of footwear, including tennis-style shoes or sneakers, other types of athletic shoes or boots, and other footwear. Further, the linear elongated protrusion may be tapered to a forward-facing point on the sole or footwear to which the sole is attached. In still yet other modifications, the linear elongated protrusion may extend from the bottom surface of the sole up through the top surface of the sole to make slight contact with the wearer's foot, or with a thin layer underneath the wearer's foot. Other embodiments may be within the scope of the following claims. 

1. A sole for footwear for unstable environments, the sole comprising: a planar bottom side; a peripheral elongated protrusion extending down from the planar bottom side along a periphery of the sole and having a gap between a forefoot portion and a rear foot portion of the sole; and a linear elongated protrusion extending down from the planar bottom side substantially in the middle of the peripheral elongated protrusion.
 2. The sole in accordance with claim 1, wherein the peripheral elongated protrusion and linear elongated protrusion have a semicircular cross section.
 3. The sole in accordance with claim 1, wherein the peripheral elongated protrusion and linear elongated protrusion are flexible.
 4. A stability and traction structure for a footwear sole, the stability and traction structure comprising: a first arc structure extending along a forefoot portion of the sole; a second arc structure extending along a rear foot portion of the sole and having an open end that faces an open end of the first arc structure, the second arc structure being separated from the first arc structure by a gap; and a linear structure extending from within the first arc structure to within the second arc structure.
 5. The stability and traction structure in accordance with claim 4, wherein the first arc structure and second arc structure includes at least one semicircular U-shaped tube.
 6. The stability and traction structure in accordance with claim 4, wherein the first and second arc structures and the linear structure are flexible.
 7. A sandal comprising: a sole having a top side and bottom side; a strap connected to the top side of the sole for fastening to a foot of a wearer of the sandal; and a first elongated protrusion extending down from the bottom side along a periphery of a forefoot portion of the sole and a second protrusion extending down from the bottom side along a periphery of a rear foot portion of the sole.
 8. A sandal in accordance with claim 7, further comprising a third elongated protrusion extending down from a medial portion of the bottom side and bridging the forefoot and the rear foot of the sole.
 9. A sandal comprising: a sole having a top side and bottom side; a strap connected to the top side of the sole for fastening to a foot of a wearer of the sandal; and a peripheral elongated protrusion extending down from the bottom side along a periphery of the sole and having a gap between a forefoot portion and a rear foot portion of the sole.
 10. A sandal comprising: a sole having a top side and a substantially planar bottom side; a strap connected to the top side of the sole for fastening to a foot of a wearer of the sandal; and traction members extending down from the substantially planar bottom side, the traction members comprising a peripheral elongated protrusion extending down from the bottom side along a periphery of the sole and having a gap between a forefoot portion and a rear foot portion of the sole, the traction members further including a central linear protrusion within the peripheral elongated protrusion.
 11. An article comprising: footwear; and a sole connected to an underside of the footwear, the sole having a stability and traction mechanism comprising: a first arc structure extending along a forefoot portion of the sole; a second arc structure extending along a rear foot portion of the sole and having an open end that faces an open end of the first arc structure, the second arc structure being separated from the first arc structure by a gap; and a linear structure extending from within the first arc structure to within the second arc structure.
 12. The article in accordance with claim 11, wherein the footwear is a sandal.
 13. The article in accordance with claim 11, wherein the footwear is a boot.
 14. The article in accordance with claim 11, wherein the footwear is a sand shoe.
 15. The article in accordance with claim 11, wherein the footwear is a tennis shoe. 